Evidence is presented to substantiate and more precisely define the postulate that catecholamine neucoltransmitters may be released by a neuronal transport process distinct from exocytosis. This is a continuing investigation of a model synaptic system consisting of a calcium dependent release of 3H-norepinephrine (3H-NE) from rat heart slices incubated in a Na ion deficient medium. It appears that a calcium dependent process directs norepinephrine loaded intraneuronal binding sites to a transport site on the plasma membrane. The 3H-NE appears to be passed directly from its binding site to the outward transport system. Amines therefore can be transported across an intact membrane without involving a process of exocytosis. Reserpine and Li ion appear to disrupt this process since they elicit a calcium independent release of deaminated metabolites.